export function Inject1(): ParameterDecorator {
  return (target: Function, propertyKey: string, parameterIndex: number) => {
    // 说明target是类本身
    console.log('Inject1', target);
  }
}
export function Inject2(): ParameterDecorator {
  return (target: Object, propertyKey: string, parameterIndex: number) => {
    // Inject2 {} target是Person类的原型
    console.log('Inject2', target);
  }
}

class Person {
  constructor(@Inject1() a: number) {
    
  }
  method(@Inject2() b: number) {

  }
}